A reference line known as a baseline is set in the digital fonts used in DTP, and in the case of CJK (ideographic characters such as Chinese, Japanese, Korean, etc.) fonts, which include Japanese fonts, a baseline for each character is usually set. When performing line typesetting, if Japanese text and European-language text are mixed together in one text line, a common baseline is used for the respective fonts in order to adjust the relative positional relationship of Japanese text and the European-language text.
FIG. 13 shows the situation where line typesetting text contains a mixture of Japanese and a European language. The first five characters, “utsu” through the first “X” from the left, are created in a Japanese font, and the next five characters, “angstrom” through “x”, are created in a European-language font. In the Japanese font, a single character is arranged inside essentially square-shaped embox 21 (also referred to as “imaginary body”). Embox 21 has a top part 21a, middle part 21b, and bottom part 21c. The vertical distance between the top part 21a and bottom part 21c of the embox 21 demarcates the height of the embox. In addition, a baseline 21d is set for the embox for these Japanese characters. European-language fonts, on the other hand, have an ascender line 31a, a cap line 31b, a baseline 31d, and a descender line 31c. The vertical distance between cap line 31b and baseline 31d sets the cap height, i.e. the height of a European-language en uppercase letter, an en being half the width of an em. In FIG. 13, line typesetting is performed by coordinating baseline 21d for Japanese fonts and baseline 31d for European-language fonts.
However, while a baseline is set in CJK fonts, including Japanese fonts, in Japanese fonts the baseline position has no direct significance on the relationship with the embox, so the baseline is independently and optionally set by the font designer. Therefore the position of the baseline is not identical in all CJK fonts, and is as a general principle different for each font. When a person considers whether the line typesetting condition of text containing the mixture of Japanese and a European language shown in FIG. 13 is suitable, and replaces one font of Japanese characters with a different font of Japanese characters, that person can expect a line typesetting situation that is different from the one shown in FIG. 13. The baseline on the Japanese or European-language side will be vertically offset with regard to the other baseline, and needs to be repositioned. Therefore it is necessary to use a computer mouse and manually correct the position, or input numerical values via a keyboard and move the text.
In addition, when character dimensions (for example point dimensions) in a given font change, the absolute position becomes more offset as the size of the characters increases, even when the relative position of the baselines is the same. Therefore, as shown in FIG. 14, when characters with different point dimensions in the same font are coordinated on coordination line 23 using their respective baselines, the lower part of the big characters projects downward compared to the small characters. That is, in emboxes 21 of different sized characters in FIG. 14, a part of the bottom of the big embox projects downward by exactly Δh compared to the small embox. This sort of line typesetting state is not permitted in Japanese typesetting, and therefore it is necessary to use a mouse or keyboard and manually correct the line typesetting.